Acoustic headsets having sound-transmitting tubes are fitted with earpieces designed to engage the wearer's outer ear. Such earpieces have a central hub that receives the acoustic tube, and a flange projecting symmetrically from the hub which is intended to seal against the outer ear in the region of the ear canal, and to become deformed as the wearer adjusts the center of the earpiece into position communicating effectively with the ear canal. While the purpose is well conceived, the result has been poor. Few users are able to adjust the central passage of the earpiece opposite the ear canal, because the flange, despite its supple quality, nevertheless resists placement of the earpiece to the desired sound-coupling position.